1. Field of the Invention
The present invention relates to an image forming apparatus having an insert sheet feeding unit other than a print sheet feeding unit.
2. Description of the Related Art
When two groups of printed sheets, for example sheets printed by a color printer and sheets printed by a monochrome printer, are collated together, manual techniques require a user to collate the two groups by himself or herself. To solve this problem, it has been proposed to provide a color printer with an inserter, so as to feed insert sheets. For example, Japanese Patent Application Laid Open No. 8-274974 describes a situation in which print data for both monochrome pages and color pages are printed and collated together. First, monochrome print data is sent from a computer to a monochrome printer for printout of monochrome pages. A user takes the monochrome pages and places them on an inserter or specific feeder of a color printer. Thereafter, the color print data is sent to the color printer that prints out color pages and collates the color pages together with the monochrome pages.
A problem arises with such an arrangement when the color printer is connected to a network connected to a plurality of computers. Specifically, the monochrome pages mounted on the feeder for one user can become accidentally collated with color pages printed by another user.